Control for internal combustion engines

ABSTRACT

A distributor for internal combustion engines having a centrifugally operated and a vacuum operated spark timing control with a switch in the primary circuit of an ignition coil operated by a throttle valve and the switch connected to a circuit breaker system controlled by centrifugal operation and a further circuit breaker system connected and influenced by a vacuum operated control.

United States Patent References Cited UNITED STATES PATENTS 7/1929Bohlman......................

71 l MW 31 1,897,704 2/1933 Mallory 1,992,383 2/1935 Mal1ory 2,103,34812/1937 Boyce......

Primary Examiner-Laurence M. Goodri e Attorney-Watson, Cole, Grindle andWatson o. 6 n mu mm y [54] CONTROL FOR INTERNAL COMBUSTION ABSTRACT: Adistributor for internal combustion engines having a centrifugallyoperated and a vacuum operated spark n m m mn m NC 5 .m ElUF HUM HUB

coNTRol, so: mmrtnAL-coMBusTroN ssc'mss This invention relates to adistributor for the engines of motor vehicles with a centrifugallyoperated and a vacuum operated spark control.

Known distributors of this type have only one circuit breaker upon whichthe centrifugally operated and the vacuum operated spark controls bothact together. For reasons which are to .be found in the type ofconstruction of the two control elements, it is not possible in the caseof this arrangement to achieve delayed firing during idling, of themotor which is desirable for the purpose for good combustion, and at thesame time to achieve an irregular or sudden adjustment to a spontaneousignition during acceleration. Since preference is given to goodacceleration above all in the case of opening of the throttle valve fromthe idling position, a relatively high advance sparking is selected asthe basic setting. Thus, one must consider in the case of idling of themotor with an advance sparking that is somewhat too high and which inturn results in too high an idling speed. ln order to lower the idlingspeed, the throttle valve therefore is set to an almost complete closingposition. The consequence of this is that the engine in the idlingstate, but above all under thrust, will obtain, because the air supplynow is much too small with simultaneously too little content, a superrich mixture, which, being burned incompletely, reaches the open airthrough the exhaust.

An object of the invention resides in making an ignition adjustment forthe purpose of decontamination of the exhaust gas in such a manner thatduring idling and under thrust, one will obtain a good combustion andcomplete burning of the fuel without adversely affecting the runningbehavior as a result thereof.

According to the invention, the solution of the problem consists in thata switch operated by the throttle valve or its rod system, isprovided inthe primary circuit of the ignition coil, by which switch, with thethrottle valve closed up to the idling position, only the circuitbreaker system influenced by the centrifugally operated control, isswitched on and in every open position of the throttle valve anothercircuit breaker system influenced only by the vacuum operated control isswitched in.

Appropriately, the area of adjustment of the centrifugally operatedadjustment amounts to after to 30 before the upper dead center of thecrankshaft and the range of the vacuum operated control amounts to 10before to 35 before the upper dead center of the crankshaft. As afurther object of the invention, both circuit breaker systems have beenarranged one above the other in the distributor housing and they haveone common driving shaft carrying the two cams.

As a result of this invention, it will be possible to make the basicsetting of the two spark controls independent of one another andstaggered in relation to one another, as desired. The firing point inidling therefore can be set to late," so that the throttle valve can beopened further, without increasing the idling speed as against an idlingspeed in the case of spontaneous ignition. As a result thereof, in thecase of all operating states while traveling with an idling position ofthe throttle valve, an improved filling of the cylinders with anincreased share of air in the mixture will be achieved. In connectionwith the centrifugally operated control which becomes effective athigher speeds,'one will achieve good combustion not only during idlingbut also under thrust and the omission of exhaust gases will bedecreased to tolerable values. On the other hand, the vacuum operatedcontrol can be set to an optimum spontaneous ignition independently ofwhat has been stated so that in the case of a transition from idling toacceleration and uniform travel, the ignition will switch overspontaneously from "late to early," and especially good values ofacceleration, which cannot be achieved otherwise, and transitions willbe achieved. 1

Further objects will be apparent from the following description whenconsidered in connection with the accompanying drawing which shows thestructure as a perspective view with wiring connections.

The distributor shown schematically in FIG. I, with its conprising twocams driven in timed tacts 1,2, 3 and 4 in the distributor head, leadingto the spark plugs, has two circuit breakers 5 and'6 arranged one abovethe other, which are operated by cams 7 and 8 respectively seated on thedistributor shaft. For each of the circuit breakers 5 and 6 a separateignition control of the design used in the trade, has beenprovided andto be sure, a centrifugally operated control 9 for the upper breaker 5and for the lower breaker 6 a vacuum operated control 10. in the case ofthe centrifugally operated control 9, the adjustment takes place in aknown manner by two centrifugal weights 1], which adjust, uponincreasing speed, a driver 12 in the direction of rotation, by means ofcam 7 which is rotatable on the distributor shaft. The vacuum box of thevacuum operated control 10, has been attached as is customary by a pipeconnection 13 to the intake pipe 14 of the carburetor; Upon opening thethrottle 15, the vacuum in the suction pipe of the engine will act onthe membrane or diaphragm 16 of the control 10, which membrane willrotate a plate 17 with the circuit breaker 6 located thereon counter tothe rotational direction of the cam 8 by means of a pull rod attached tosaid membrane and, as a result thereof, will increase the advancesparking.

The cables of the two circuit breakers 5 and 6, which have been switchedin parallel, lead to a switch 21 located in the primary circuit of theignition coil 20, which switch is operated by the lever of the throttlevalve 15 and has two positions. In the case that the throttle valve 15is closed, only the circuit breaker 5 with the centrifugally operatedcontrol 9, has been switched on and in the case of an opened throttle 15only the circuit breaker 6 with the vacuum-operated control 10 has beenswitched on.

in the diagram according to FIG. 2, the adjusting curve F of thecentrifugally operated control 9 (basic setting 10 after upper deadcenter, adjusting range up to 30 before upper dead center of thecrankshaft) and the full load adjusting curve U of the vacuum-operatedcontrol 10 (basic setting 10 before upper dead center, adjusting rangeup to 35 before upper dead center of the crankshaft) have been plottedabove the engine speed or motor revolutions n. The idling speed has beendesignated with n,, r.p.m. In the case of opening of the throttle 15,the ignition is spontaneously switched over from the basic setting of 10after the upper dead center of the centrifugally operated control 9 tothe basic setting of 10 before upper dead center of the'vacuum-operatedcontrol 10. The ignition setting will then, in the case of furtheracceleration and in the case of level travel, and as long as thethrottle valve 15 remains opened, follow the course of the curve U ofthe vacuum-operated control 9. By decreasing the gas and up to closingof the throttle 15, one shifts back to the centrifugally operatedcontrol 9. The ignition setting will then change in the case of thrustsof the vehicle (delay or else acceleration in the case of downhilltravel) in correspondence with the course of the adjusting curve F.

lclaim:

1. An ignition distributor for a spark ignition engine comrelation withthe engine, a pair of circuit breakers operated independently each ofthem by one of said cams, engine speed responsive means connected withone of said cams to retard the timed opening of the first of saidcircuit breakers with decreases in engine speed, a vacuum-operatedcontrol connected to said distributor and operated by pressures sensedin the induction system of said engine to adjust the timed opening ofthe second of said circuit breakers according to engine load and speedthroughout a range of throttle open positions in which timed opening ofthe second of said circuit breakers is advanced with respect to thetiming of the first when the engine is idling with the throttle closed,parallel circuits connecting each circuit breaker with the primary ofthe ignition coil, switch means in each of said parallel circuits, andmeans for operating said switch means to close one of said parallelconnected circuits to the first said circuit breaker and open the otherwith the throttle closed to idle positions and to close the other ofsaid parallel connected circuits to the second said circuit breakerandopen the other with the throttle in the said range of open positions.

1. An ignition distributor for a spark ignition engine comprising twocams driven in timed relation with the engine, a pair of circuitbreakers operated independently each of them by one of said cams, enginespeed responsive means connected with one of said cams to retard thetimed opening of the first of said circuit breakers with decreases inengine speed, a vacuumoperated control connected to said distributor andoperated by pressures sensed in the induction system of said engine toadjust the timed opening of the second of said circuit breakersaccording to engine load and speed throughout a range of throttle openpositions in which timed opening of the second of said circuit breakersis advanced with respect to the timing of the first when the engine isidling with the throttle closed, parallel circuits connecting eachcircuit breaker with the primary of the ignition coil, switch means ineach of said parallel circuits, and means for operating said switchmeans to close one of said parallel connected circuits to the first saidcircuit breaker and open the other with the throttle closed to idlepositions and to close the other of said parallel connected circuits tothe second said circuit breaker and open the other with the throttle inthe said range of open positions.